In China, WeChat is not only beating SMS and social networks – it’s also a threat to Alipay, the country’s equivalent to PayPal.

The mobile chat app, which now claims 270 million users and 500 million registered accounts, has effectively become the central communications platform for anyone in China with a smartphone. Increasingly, it’s looking like it will be a major payments platform, too.

Overnight, smartphone maker Xiaomi sold 150,000 of its new Mi3 smartphones purely via WeChat, according to The Next Web. The batch sold out in 9 minutes and 55 seconds. This is not a case of people punching their credit card details into a page linked to from within WeChat. This is a case of WeChat being used as a mobile wallet and storefront.

This news comes soon after more than 80,000 people bought products solely via WeChat during China’s “Double 11″ online shopping festival, which is the country’s version of Cyber Monday. That number doesn’t seem huge in its own right, but the WeChat purchases were limited to a single promotion via the site 51buy, and only for residents in Beijing, Shanghai, Shenzhen, and Guangzhou. Orders on the site that day totaled 600,000, meaning WeChat, in its first year as a payments tool, represented 13 percent of the site’s sales.

WeChat’s owner, Tencent, has been pretty cautious with its rollout of the app’s payment functionality. In September, however, it ran a promotion in which WeChat users could scan QR codes on vending machines in subway stations to purchase physical goods, such as sodas and snack foods, all at a discount.

A few days ago, I wrote about how WhatsApp, which is the world’s leading mobile chat app in terms of active users, has a problem. It’s not that it doesn’t provide a good messaging experience, or that not a lot of people are using it. It has been around since 2009 and has been the first port of call for many seeking an alternative to SMS, on feature phones as well as smartphones. Instead, its problem is that it is limited only to messaging, which is now a commodity.

By being singularly focused on messaging, WhatsApp is missing the opportunity to create new engagement channels and revenue lines. While WeChat, Japan’s Line, and South Korea’s KakaoTalk offer payments, games, and social network-like features, WhatsApp only has its instant messaging capability. WeChat’s emergence as a force in payments, one that could evolve into one of China’s primary players in ecommerce, throws WhatsApp’s weakness into stark relief.

But something else does, too. Games.

WhatsApp doesn’t look even close to being able to take advantage of its giant global userbase in order to drive people to or between games, let alone capture some of the upside from them. WeChat, like Line and KakaoTalk, clearly is. According to mobile analyst Benedict Evans, the first five games released on WeChat have collectively passed 570 million downloads in the space of three months. (Note: I’m waiting for Benedict to provide a source for that claim, but he’s usually reliable.) Meanwhile, one WeChat game, “Airplane War,” is proving so addictive that it’s putting people in hospital.

It’s probably time we stop referring to WeChat, Line, and KakaoTalk as “chat” apps. The name doesn’t do them justice.